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Old 03-19-2021, 01:42 PM   #1
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refrigerator

How RV Refrigerators Work
There are 2 brands of refrigerators commonly found in RVs:

Dometic RV refrigerator
Norcold RV refrigerator
Both operate under the same principles.

This is how an RV refrigerator operates:

A sealed cooling element is heated — either with a gas flame or an electric heating element.
The cooling unit amounts to a series of tubes filled with an ammonia-based liquid — as heat is applied, the fluid circulates through the cooling unit drawing the heat out of the refrigerator.


If The Refrigerator Isn’t Cooling Properly…
When an RV refrigerator starts failing (not cooling as well as it should), it means the fluid is no longer circulating properly through the cooling unit.

The nice thing about RV refrigerators is there are no moving parts. There are no pumps to wear out, and no compressors either. All the work is done simply by heating liquid — like in your coffee pot. When it boils, it perks the coffee. When the ammonia is heated, it circulates.

If the cooling unit develops a leak, you will smell ammonia in a big way. This isn’t a very common occurrence, but if it does happen, you will immediately know where the problem is.


What Happens When An RV Refrigerator Isn’t Used
More often than not, the problem with an RV refrigerator is time combined with lack of use.

As RV refrigerators age, the ammonia liquid can create sediment that settles to the bottom of the cooling unit. This sediment will hinder the ability of the ammonia to circulate properly through the cooling unit. As the sediment builds up, the refrigerator will cool less and less.

A refrigerator that is used once or twice a year over a period of 5 or 6 years is much more likely to plug up than one that is in continual operation. Constant movement keeps any sediment suspended in the fluid — which ultimately prevents any accumulation from occurring. This is when I use the DA sander that has made many of them work better or start working . Back in the 80's my dads refrigerator stopped working he talked to several RV repair men one old timer told him it's a lot of work .But remove refrigerator tape doors closed roll it in grass 10 times then hook it up and it should work .Not wanting to remove it I came up with the idea of using the DA sander and his refrigerator started working then I had to go to his friends camper did the same it started working and the story goes on. This was all started before the Internet
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Old 03-19-2021, 01:48 PM   #2
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So what do you do with the DA sander to make the refrigerator work?...lay it on the condensing unit with the DA sander locked on and let it vibrate for a few days?
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Old 03-19-2021, 01:51 PM   #3
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https://d2culxnxbccemt.cloudfront.ne...frigerator.jpg

Put DA sander on absorption tank
or absorber tank in picture
I just had to do it 10 min. If it doesn't work try another 10 min until it works .Not to long at one time or you might have tube failure
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Old 03-19-2021, 02:04 PM   #4
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https://www.amazon.com/Ingersoll-311...xpY2s9dHJ1ZQ== DA sander
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Old 04-01-2021, 09:35 PM   #5
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In our 2017 21DS, we have a Dometic 2-way fridge. The problem we've run into is that, after about four days camping, it just keeps getting colder - to about 25F, if we let it go. The slider adjustment has no effect. Our interim solution is to just turn it off for a day, until it's into the 40s, turn it back on. Monitor the temp, and repeat as needed.

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Old 04-02-2021, 10:18 AM   #6
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Your thermistor is likely bad . Another thing the thermistor should be moved to the third fin on coils . If you do a search you will find how to test thermistor with volt meter . The slider thing is the thermistor .
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Old 04-02-2021, 10:22 AM   #7
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This is the thermistor don't know if this fits just using it to show you what it looks like https://www.amazon.com/Dometic-38512...s%2C205&sr=8-5
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Old 04-02-2021, 10:39 AM   #8
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Quote:
Originally Posted by doanshop View Post
Your thermistor is likely bad . Another thing the thermistor should be moved to the third fin on coils . If you do a search you will find how to test thermistor with volt meter . The slider thing is the thermistor .
Where the thermistor sits is dependent on the unit not the same in evey fridge . norcold could have different locations depending on the model same as dometic . old school for clogged passages was to remove fridge and turn upside down for awhile . never heard of rolling it on the lawn . there are many reason for the fridges to quit cooling well clogged ports are not common on newer units and more of a problem on older units . when thermistors go bad it's normally create a warmer fridge not colder . some fridges have temp setting others do not and relay on the thermistors solely for temp control . remove thermistor and fridge should go to max cool as a default .
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Old 04-02-2021, 10:56 AM   #9
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Finally found a helpful video - the problem was that the sensor was not clipped into the slider. (we wondered how moving the plastic thing up or down could possibly affect temperature by itself!)

DOH!
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Old 04-02-2021, 04:02 PM   #10
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Quote:
Originally Posted by MR.M View Post
Where the thermistor sits is dependent on the unit not the same in evey fridge . norcold could have different locations depending on the model same as dometic . old school for clogged passages was to remove fridge and turn upside down for awhile . never heard of rolling it on the lawn . there are many reason for the fridges to quit cooling well clogged ports are not common on newer units and more of a problem on older units . when thermistors go bad it's normally create a warmer fridge not colder . some fridges have temp setting others do not and relay on the thermistors solely for temp control . remove thermistor and fridge should go to max cool as a default .
How many have you fixed in your life time ?
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Old 04-25-2021, 09:10 PM   #11
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How many have you fixed in your life time ?

Dozens !
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Old 04-25-2021, 09:25 PM   #12
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Finally found a helpful video - the problem was that the sensor was not clipped into the slider. (we wondered how moving the plastic thing up or down could possibly affect temperature by itself!)

DOH!
I've found that the plastic of the slider deforms with age and the thermistor falls out, even if the slider still holds onto the fin.
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Old 06-05-2021, 06:46 PM   #13
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Originally Posted by doanshop View Post
https://d2culxnxbccemt.cloudfront.ne...frigerator.jpg

Put DA sander on absorption tank
or absorber tank in picture
I just had to do it 10 min. If it doesn't work try another 10 min until it works .Not to long at one time or you might have tube failure

hi.. just getting ready to try this.. so, would the DA sander just be laid in there against the absorption tank? not like - sanding it right? (sorry, I'm SO not tool savvy). Also, was wondering if driving down a bumpy dirt road would in effect do the same thing? Thanks so much!
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Old 06-06-2021, 12:12 PM   #14
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Originally Posted by lexington03 View Post
hi.. just getting ready to try this.. so, would the DA sander just be laid in there against the absorption tank? not like - sanding it right? (sorry, I'm SO not tool savvy). Also, was wondering if driving down a bumpy dirt road would in effect do the same thing? Thanks so much!
No sandpaper just hold it to absorption tank let it vibrate tank .you need to hold it not just wedge it in there move it from bottom to side as you do it . bumpy road will do more harm to rv .
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Old 06-06-2021, 12:28 PM   #15
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Quote:
Originally Posted by chriscowles View Post
I've found that the plastic of the slider deforms with age and the thermistor falls out, even if the slider still holds onto the fin.
Mine is relatively new, and fell out of the fin clip and I didn't even realize it. They didn't allow enough slack in the thermister wire, so as you slid the clip up, it pulled out. I was able to tug on wire a little and got more play to properly position it. Fridge has no light in it, a lot of people may have never noticed.
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Old 06-06-2021, 12:42 PM   #16
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Snip-The-Tip Thermistor Replacement (for Dometic Fridges)

I replaced the fridge's sliding thermistor thingy with the above device and haven't looked back. It was very simple to install and the variable resistor allows you to easily fine-tune the temperature. Adding a refrigerator circulation fan also helped to distribute the cold air.
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Old 06-06-2021, 01:01 PM   #17
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Thanks Theo, seems like a reasonable upgrade for 30 bucks. The sliding thermister doesn't 'fine tune' diddly! Even slid towards bottom of fin, ice bin is well below zero and fridge gets down to low 30's. Then when I get to enjoy Southern heat, all bets are off and it's a struggle to keep temp low enough, especially since my spot has sun beating on fridge vent side all day.
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Old 06-06-2021, 01:42 PM   #18
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Stack fan will help cooling absorption refrigerators. Fitting one can be a significant project.

-- Chuck
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Old 06-06-2021, 01:48 PM   #19
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Seems to be the sun that really hurts efficiency. Check out what this guy did. https://www.trailerlife.com/tech/10-...h-cool-fridge/
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Old 06-06-2021, 02:19 PM   #20
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I've removed dozens and turned them upside down and then tested them the next day. Worked 90% of the time, sure wish I would have tried to vibrate them loose first!
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